import math


def is_prime(n: int):
    if n < 2:
        return False
    elif n == 2:
        return True
    elif n % 2 == 0:
        return False
    sqrt_num = int(math.sqrt(n))
    for i in range(3, sqrt_num):
        if n % i == 0:
            return False
    return True


if __name__ == "__main__":
    n = int(input())
    min_n = max(4, n - 100)
    max_n = n + 100

    for i in range(min_n, max_n + 1):
        if not is_prime(i):
            print(i)
            break